Bodies such as automobile engines and various kinds of machinery and apparatus become coated with a waste material. This waste material may be oil, e.g., petroleum, based, being a mixture of lubricating oil and dust or dirt. The lubricating oil soils the outside of the automobile engine, being deposited there when oil is spilled when added to the engine to replace oil which has leaked or been burned in the engine. Also, oil fumes may condense on the exterior of the engine or carry liquid oil droplets which are deposited on the engine, and in either case, the liquid engine oil captures dirt and dust particles. The result is a petroleum based mass, somewhat spongy, which over time builds to a substantial thickness on the exterior of the engine. This petroleum based waste is undesirable, and its removal and proper disposal presents a problem since petroleum waste may contain undesirable constituents such as lead and zinc, which contaminate the environment.
Another, and related problem, is in connection with removal of water based material from automobiles, and other machinery. Water based waste is deposited on the automobile or other machinery, for example, in the engine compartment, in the wheel wells, and on the exterior. Causes for such deposits include rain, snow, and wet pavements as the primary sources of the water; with that water there is mixed dust, dirt and various atmospheric particles. Removal of the water based waste does not tend to contaminate the environment, but heretofore, an excessive amount of potable water has often been used to effect the task of cleaning the water based waste from the automobile or the machinery.
To facilitate the removal of the petroleum based waste on the exterior of an internal combustion engine, there is widely used a chemical composition which is sprayed on the petroleum based waste from a spray can: a spray can is typically a small hand held cylindrical container containing a propellant, which is usually gaseous, and a chemical material in liquid form. At one end of the cylindrical metal container, there is provided a spray nozzle, which is depressed to open a valve to permit the liquid material to escape and to be delivered to the petroleum based waste. The liquid material dissolves the oil based waste to lessen or weaken the adherence of it to the external surfaces of the internal combustion engine, and may contain a detergent.
While the sprayed waste removal liquid loosens or weakens the adherence of the petroleum and water based waste to the internal combustion engine, it is usually required that it be removed by mechanical force. Such force has been most conveniently delivered by utilizing a conventional garden hose to discharge water against the waste and the internal combustion engine, the impact of the water knocking the petroleum based waste loose from the internal combustion engine. The garden hose was typically connected to a faucet connected to a domestic water system, water passing into the water system through a pressure control valve which reduces the pressure in the system to a standard, approximately 25-60 psig. A similar water pressure is provided where the origin of the water is a well and pump system: the available water pressure in such systems is generally the same as that in the conventional water systems which supply water to a large number of residences.
The engine cleaning process, as above described, has been typically performed by individual automobile owners at their place of residence. After the water from the garden hose had dislodged the petroleum and water based waste, the area under the automobile was cleaned by flushing with water from the hose, either to clean a driveway, or to disperse the waste into a lawn. The petroleum components of the waste were thus flushed into storm water systems, for discharge into streams and rivers, while the petroleum constituents which were dispersed in a lawn were, by the effects of natural precipitation and watering of the lawn, introduced into underground streams, and thence into surface streams and rivers. Consequently, there are two problems with the presently used method and apparatus from the point of view of environmental concerns. One is contamination of streams and rivers with hydrocarbons and other constituents of the petroleum, and the other is the utilization of an unacceptably large amount of potable water. The latter is, of course, of particular concern in those regions where potable water is in short supply.